Note:The Great Comet of 1843, formally designated C/1843 D1 and 1843 I, was a long-period comet which became very bright in March 1843 (it is also known as the Great March Comet). It was discovered on February 5, 1843 and rapidly brightened to become a great comet. It was a member of the Kreutz Sungrazers, a family of comets resulting from the breakup of a parent comet (X/1106 C1) into multiple fragments in about 1106. These comets pass extremely close to the surface of the Sun—within a few solar radii—and often become very bright as a result.

Note:The Mexican-American War was an armed conflict between the United States of America and the United Mexican States from 1846 to 1848 in the wake of the 1845 U.S. annexation of Texas, which Mexico considered part of its territory despite the 1836 Texas Revolution - http://goo.gl/dGxJ1k

Note:In the spring of 1861, tensions between the northern and southern United States over issues including state's right versus federal authority, westward expansion and slavery exploded into the American Civil War - http://goo.gl/ETtxkC

Note:The First Transcontinental Railroad was a 1,907-mile contiguous railroad line constructed between 1863 and 1869 across the western United States to connect the Pacific coast with the existing Eastern U.S. rail network - http://goo.gl/Xafdg5

Note:Spanish Influenza killed over 500,000 people in the United States, and somewhere between 20 and 40 million in what has been cited as the most devastating epidemic in history - http://goo.gl/nYVCtq